Can we grow younger?     

Saul H 《New scientist (1971)》1994,141(1913):22-24

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Kinetics study on biomass pyrolysis for fuel gas production     

陈冠益  方梦祥  ANDRIES J  骆仲泱  SPLIETHOFF H  岑可法 《浙江大学学报(A卷英文版)》2003,4(4):441-447

Kinetic knowledge is of great importance in achieving good control of the pyrolysis and gasification process and optimising system design. An overall kinetic pyrolysis scheme is therefore addressed here. The kinetic modelling incorporates the following basic steps: the degradation of the virgin biomass materials into primary products (tar, gas and semi-char), the decomposition of primary tar into secondary products and the continuous interaction between primary gas and char. The last step is disregarded completely by models in the literature. Analysis and comparison of predicted results from different kinetic schemes and experimental data on our fixed bed pyrolyser yielded very positive evidence to support our kinetic scheme. Project (No. 2001CB409600) Supported by the National Key Basic Research Program (973) of China  相似文献   

Kinetics study on biomass pyrolysis for fuel gas production   总被引：1，自引：0，他引：1  

陈冠益  ANDRIES  J.  方梦祥  骆仲泱  SPLIETHOFF  H  岑可法 《Journal of Zhejiang University. Science. B》2003,(4)

INTRODUCTIONSincebiomassisanabundant,inexpensiveandrenewableresource ,itsconversiontosyn theticfuelsandchemicalproductsappearsat tractive.Amongallkindsofbiomassconversionroutes,pyrolysisisbeinggivenincreasingatten tionsincetheprocessissimpleandmaybeopti m…  相似文献   

基于良构和劣构问题求解的教学设计模式(下)   总被引：10，自引：0，他引：10  

David H.Jonassen  钟志贤  谢榕琴 《电化教育研究》2003,(11)

虽然大多数教育家认为问题求解能力是最重要的学习结果 ,但在教学设计研究中却很少涉及问题求解的教学设计问题。本文的探究力图弥补这一不足。我们认为 ,问题可以分为良构问题 (well- structured prob-lem)和劣构问题 (ill- structured problem)两大类型。良构问题是指限定性条件的问题 ,它具有明确的已知条件 ,并在已知条件范围内运用若干规则和原理来获得同一性的解决方法 ;劣构问题的特点是具有多种解决方法、解决途径和少量确定性的条件 ,这些条件不仅不易操作 ,而且包括某些不确定性因素 ,如哪些概念、规则和原理对求解方法是必要的 ,如何将它们组织起来 ,哪种解决方法最为合适等等。对于这两大类型问题 ,本文分别讨论了学习者问题求解的模式和相应的教学设计模式 ,以支持学习者问题求解技能的发展。良构问题的求解模式是以信息加工学习理论为基础的 ,而劣构问题的求解模式则是基于一种新兴的劣构问题求解理论、建构主义和情境认知学习理论。  相似文献   

Approaching usability: a study of an academic health sciences library web site   总被引：1，自引：0，他引：1  

Ascher MT  Lougee-Heimer H  Cunningham DJ 《Medical reference services quarterly》2007,26(2):37-53

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Obituary: Bernard Theodoor Marie Tervoort: May 29, 1920,Groesbeek, the Netherlands--August 17, 2006, Bussum, the Netherlands     

Knoors H 《Journal of deaf studies and deaf education》2007,12(2):242

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Genetic analysis for brix weight per stool and its component traits in sugarcane （Saccharum officinarum）     

Liu GF  Zhou HK  Hu H  Zhu ZH  Hayat Y  Xu HM  Yang J 《Journal of Zhejiang University. Science. B》2007,8(12):860-866

Brix weight per stool (BW) of sugarcane is a complex trait, which is the final product of a combination of many components. Diallel cross experiments were conducted during a period of two years for BW and its five component traits, including stalk diameter (SD), stalk length (SL), stalk number (SN), stalk weight (SW), and brix scale (BS) of sugarcane. Phenotypic data of all the six traits were analyzed by mixed linear model and their phenotype variances were portioned into additive (A),dominance (D), additive×environment interaction (AE) and dominance×environment interaction (DE) effects, and the correlations of A, D, AE and DE effects between BW and its components were estimated. Conditional analysis was employed to investigate the contribution of the components traits to the variances of A, D, AE and DE effects of BW. It was observed that the heritabilities of BW were significantly attributed to A, D and DE by 23.9%, 30.9% and 28.5%, respectively. The variance of A effect for BW was significantly affected by SL, SN and BS by 25.3%, 93.7% and 17.4%, respectively. The variances of D and DE effects for BW were also significantly influenced by all the five components by 5.1%～85.5%. These determinants might be helpful in sugarcane breeding and provide valuable information for multiple-trait improvement of BW.  相似文献   

What good is a scientist in the classroom? Participant outcomes and program design features for a short-duration science outreach intervention in K-12 classrooms     

Laursen S  Liston C  Thiry H  Graf J 《CBE life sciences education》2007,6(1):49-64

Many short-duration science outreach interventions have important societal goals of raising science literacy and increasing the size and diversity of the science workforce. Yet, these long-term outcomes are inherently challenging to evaluate. We present findings from a qualitative research study of an inquiry-based, life science outreach program to K-12 classrooms that is typical in design and excellent in execution. By considering this program as a best case of a common outreach model, the "scientist in the classroom," the study examines what benefits may be realized for each participant group and how they are achieved. We find that K-12 students are engaged in authentic, hands-on activities that generate interest in science and new views of science and scientists. Teachers learn new science content and new ways to teach it, and value collegial support of their professional work. Graduate student scientists, who are the program presenters, gain teaching and other skills, greater understanding of education and diversity issues, confidence and intrinsic satisfaction, and career benefits. A few negative outcomes also are described. Program elements that lead to these benefits are identified both from the research findings and from insights of the program developer on program design and implementation choices.  相似文献   

In search of a new, linguistically and culturally sensitive paradigm in deaf education     

Simms L  Thumann H 《American annals of the deaf》2007,152(3):302-311

For more than a century, educators have recognized the low academic achievement of deaf children in America. Teacher training programs in deaf education historically have emphasized medical-pathological views of deaf people and deaf education rather than appropriate pedagogies that draw upon and build on deaf students' linguistic and cultural knowledge. A recent and growing interest in educating deaf children bilingually acknowledges the value of American Sign Language and English in the classroom. The authors address the dire need for prospective teachers and teacher educators to rethink their views of deaf people and, in doing so, rethink the teaching methodologies in deaf education.  相似文献   

Children with autism illuminate the role of social intention in word learning   总被引：2，自引：0，他引：2  

Parish-Morris J  Hennon EA  Hirsh-Pasek K  Golinkoff RM  Tager-Flusberg H 《Child development》2007,78(4):1265-1287

To what extent do children with autism (AD) versus typically developing children (TD) rely on attentional and intentional cues to learn words? Four experiments compared 17 AD children (M age=5.08 years) with 17 language- and 17 mental-age-matched TD children (M ages=2.57 and 3.12 years, respectively) on nonverbal enactment and word-learning tasks. Results revealed variability in all groups, but particularly within the AD group. Performance on intention tasks was the most powerful predictor of vocabulary in the AD group but not in the TD groups. These findings suggest that word learning cannot be explained exclusively by either attentional or intentional processes, and they provide evidence of a special role for intentional understanding in the vocabulary development of AD children.  相似文献